[unreadable] Osteoarthritis (OA) of the knee is common, disabling and costly. Arthroscopic surgery is used frequently in patients with OA who have not responded to nonoperative therapies. Arthroscopic lavage and debridement have been shown to be no better than sham surgery in the management of knee OA. However, most arthroscopic surgeries performed in patients with OA are not lavage and debridement, but rather arthroscopic partial meniscectomies (APM). This procedure is performed to relieve symptoms due to symptomatic meniscal tears, which are highly prevalent in patients with OA. While APM is the most frequently performed orthopaedic procedure, there have been no randomized controlled trials of the efficacy of APM for symptomatic meniscal tears in the setting of OA. [unreadable] [unreadable] In this Planning Grant application we request funds to plan a randomized controlled trial of arthroscopic partial meniscectomy in patients with symptomatic meniscal tears in the setting of knee OA. The specific aims of the proposed RCT are: 1) To establish the efficacy of arthroscopic partial meniscectomy as compared with intensified non-operative management among patients with symptomatic meniscal tear in the setting of knee OA; 2) to identify factors associated with favorable outcomes of APM; and 3) to evaluate the cost effectiveness of APM in the management of patients with symptomatic meniscal tears in the setting of knee OA. [unreadable] [unreadable] The design and conduct of a multicenter RCT is complex. A planning period would permit us to accomplish key objectives to facilitate the conduct of the trial. The objectives of the Planning Grant are to 1) develop a Manual of Operations and Procedures, 2) develop the economics core and activities, 3) finalize selection of the data management center, 3) refine estimates of participation rates and sample size requirements, 4) finalize selection of participating centers and back-up centers, 5) develop a safety and monitoring plan, and 6) establish the processes and structure for accomplishing the goals of the planning grant and the actual trial. If funded, these planning activities would enable us initiate the full trial with minimal delay. [unreadable] [unreadable]